That's not the Fett ESB clamp. Similar but different brand/style.
Proportionally it's taller than Fett's and the arms are shorter with rounded ends.
It looks close to the Maclow brand, but the Maclow doesn't have the inside rounded bit on the top corners (at least the modern ones don't, maybe vintage did). This type of clamp was used in ESB to hold pipes onto the walls of the Falcon set.